Rooftop canvas

ABSTRACT

Rooftop canvas includes a twill texture layer having a plurality of flat warp strips extending in a longitudinal direction and a plurality of flat weft strips extending in a lateral direction perpendicular to the longitudinal direction. An imaginary line passing through an intersection of one of the flat weft strips and one of the flat warp strips and an intersection of another flat weft strip adjacent to the flat weft strip and another flat warp strip adjacent to the flat warp strip is inclined relative to the longitudinal direction and the lateral direction. The twill texture layer is superimposed on a first covering layer. The rooftop canvas can further include a second covering layer, with the first covering layer sandwiched between the twill texture layer and the second covering layer.

BACKGROUND OF THE INVENTION

The present invention relates to a building material and, moreparticularly, to rooftop canvas.

There are more storms, hurricanes, and tornados due to climate warmingand extreme climates. The building materials, including rooftop canvas,should be adjusted according to the climate change. Rooftop canvas is amodern building material and use advanced polymers to shield ultravioletrays and provide protection. In addition to withstanding strong sunlightand providing resistance to decomposition, the rooftop canvas possessesexcellent resistance to aging due to heat.

Safety is the top priority while installing the rooftop canvas onrooftops. However, a worker slips easily on conventional rooftop canvasmade of asphalt when the rooftop canvas is heated, moistened, or stainedwith oil. Furthermore, the conventional rooftop canvas has low tearstrength. Thus, the safety of the worker on the rooftop canvas is risky.

BRIEF SUMMARY OF THE INVENTION

Rooftop canvas according to the present invention includes a twilltexture layer having a plurality of flat warp strips extending in alongitudinal direction and a plurality of flat weft strips extending ina lateral direction perpendicular to the longitudinal direction. Animaginary line passing through an intersection of one of the pluralityof flat weft strips and one of the plurality of flat warp strips and anintersection of another of the plurality of flat weft strips adjacent tothe one of the plurality of flat weft strips and another of theplurality of flat warp strips adjacent to the one of plurality of flatwarp strips is inclined relative to the longitudinal direction and thelateral direction. The twill texture layer is superimposed on a firstcovering layer.

Each of the plurality of flat warp strips and the plurality of flat weftstrips includes at least one corrugated face, and the twill texturelayer includes at least one corrugated surface.

Preferably, the rooftop canvas further includes a second covering layer.The first covering layer is sandwiched between the twill texture layerand the second covering layer.

Each of the plurality of flat warp strips and the plurality of flat weftstrips is made of polyolefin, preferably polypropylene.

The first covering layer is made of polyolefin, preferablypolypropylene.

The second covering layer is made of one of a thermoplastic elastomer, apolyolefin elastomer, or a polyolefin plastomer, or a mixture ofpolypropylene and at least one of a thermoplastic elastomer, apolyolefin elastomer, and a polyolefin plastomer.

The rooftop canvas according to the present invention possessesanti-slipping properties, light shielding properties, and waterpermeation resistance.

The present invention will become clearer in light of the followingdetailed description of illustrative embodiments of this inventiondescribed in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of rooftop canvas according to thepresent invention.

FIG. 1A shows an enlarged view of a circled portion of FIG. 1.

FIG. 2 is a perspective view illustrating an anti-slip test of therooftop canvas according to the present invention.

FIG. 3 is a perspective view illustrating another anti-slip test of therooftop canvas according to the present invention.

FIG. 4 shows a water permeation resistance test of the rooftop canvasaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, rooftop canvas 1 according to the presentinvention includes a twill texture layer 11 including a plurality offlat warp strips 111A extending in a longitudinal direction and aplurality of flat weft strips 111B extending in a lateral directionperpendicular to the longitudinal direction. An imaginary line passingthrough an intersection of one of the flat weft strips 111B1 and one ofthe flat warp strips 111A1 and an intersection of another flat weftstrip 111B2 adjacent to the flat weft strip 111B1 and another flat warpstrip 111A2 adjacent to the flat warp strip 111A1 is inclined relativeto the longitudinal direction and the lateral direction (see theimaginary lines in FIG. 1).

In the form shown in FIGS. 1 and 1A, after weaving the flat warp strips111A and the flat weft strips 111B together to form the rooftop canvas1, a first one of the flat warp strips 111A is located below a firstflat weft strip 111B and located above second, third, and fourth flatwell strips 111B. Likewise, a second one of the flat warp strips 111A islocated above the first three flat weft strips 111B and located belowthe fourth flat weft strips 111B. An imaginary line passing through afirst intersection 111C1 of the first flat warp strip 111A1 and thefirst flat weft strip 111B1 and a second intersection 111C2 of thesecond flat warp strip 111A2 and the second flat weft strip 111B2 isinclined. Other intersections of flat warp strips 111A and flat weftstrips 111B are similar to this arrangement.

Since the flat warp strips 111A and the flat weft strips 111B intersectwith each other, are mutually superimposed at different sections, andpress against each other, the surfaces of the twill texture layer 11 arerugged, uneven, and fluffy. Each of the flat warp strips 111A and theflat weft strips 111B has a width in a range from 1.5 to 5.0 mm. Thewidth of the flat warp strips 111A can be different from the width ofthe flat weft strips 111B to obtain a twill texture layer H of a desiredpattern. Each of the flat warp strips 111A and the flat weft strips 111Bhas at least one corrugated face such that the twill texture layer 1includes at least one corrugated surface that is more rugged, uneven,and fluffy.

The rooftop canvas 1 further includes a first covering layer 12. Thetwill texture layer 1 is superimposed on the first covering layer.

The rooftop canvas 1 has anti-slipping properties. Specifically, when aworker wearing rubber shoes stands on the surface of the twill texturelayer 11, the bottom faces of the rubber shoes bite into the surface ofthe twill texture layer 11 without slipping. It has been proved in teststhat slipping would not occur even if the rooftop canvas 1 is placed ona rooftop having an inclination angle of 34 degrees. The safety of theworker on the rooftop canvas is assured.

With reference to FIG. 2, in an anti-slipping test, the rooftop canvas 1according to the present invention is placed on a carrier board 33supported by a rod 32 connected to an angle adjuster 31. The angleadjuster 31 can be operated to change the inclination angle of thecarrier board 33, and the inclination angle of the carrier board 33 isindicated by an angle indicator 34. A weight 35 is placed on the carrierboard 33 to simulate the load. The test result shows that the rooftopcanvas 1 according to the present invention possesses excellentanti-slipping properties.

FIG. 3 shows another anti-slipping (friction) test of the rooftop canvas1 according to the present invention. The rooftop canvas 1 is placed ona plate 37, and a weight 35 is placed on the rooftop canvas 1. A pullingforce displayer 36 is provided to apply and measure a force for pullingthe weight 35. The test result shows that the rooftop canvas 1 accordingto the present invention possesses excellent anti-slipping properties.

The rooftop canvas 1 according to the present invention also possesseslight shielding properties. Since at least one face of each of the flatwarp strips 111A and the flat weft strips 111B is corrugated, at leastone surface of the twill texture layer 11 is corrugated and, thus,rugged, uneven, and fluffy. Each of the flat warp strips 111A and theflat weft strips 111B can shield and reflect light beams from differentangles.

The rooftop canvas 1 according to the present invention also possesseswater permeation resistance. Since the flat warp strips 111A and theflat weft strips 111B are corrugated, are woven with each other, areoverlapped with each other, and squeeze each other, they fill gapstherebetween and, thus, possess water permeation resistance.

With reference to FIG. 4, in a test of water permeation resistance, therooftop canvas 1 according to the present invention is placed in a watertank 24 at an inclined angle. Water is supplied from a water pipe 25through a valve 21, and a pressure gauge 22 is provided to measure thewater pressure. Water passes through a sprinkler 23 to the rooftopcanvas 1, falls into the water tank 24 and is drained via a drain 26 inthe bottom of the water tank 24. The test result shows that the rooftopcanvas 1 according to the present invention possesses excellent waterpermeation resistance.

The rooftop canvas 1 can further include a second covering layer 13. Thefirst covering layer 12 is sandwiched between the twill texture layer Hand the second covering layer 13. The second covering layer 13 providesenhanced water-resistant effect. In the form shown, each of the flatwarp strips 111A and the flat weft strips 111B is made of polyolefin(polymers obtained from addition polymerization). These polymers areobtained from polymerization of many identical or different simpleolefin molecules and possess better water permeation resistanceproperties. The first covering layer 12 is preferably made of polyolefinto enhance the water permeation resistance properties. The polyolefinfor producing the flat warp strips 111A, the flat weft strips 111B, andthe first covering layer 11 is preferably polypropylene (PP), obtainingeffects of light weight and resistance to chemicals and heat.

The second covering layer 13 is made of one of a thermoplastic elastomer(TPE), a polyolefin elastomer (POE), or a polyolefin plastomer (POP), ora mixture of polypropylene (PP) and at least one of a thermoplasticelastomer (TPE), a polyolefin elastomer (POE), and a polyolefinplastomer (POP).

Thermoplastic elastomers (TPE), or referred to as thermoplastic rubbers(TPR), possess properties of both of rubber and thermoplastic plastics.They are in a molten state and can be easily processed at hightemperatures. At normal temperature, they have better tensile strengthand are easy to process with low energy consumption and can be recycled.

Polyolefin elastomer (POE) is an elastic composite material havingexcellent toughness and excellent resistance to aging. Polyolefinelastomer has better flowability and is compatible with poleolefin.

Although specific embodiments have been illustrated and described,numerous modifications and variations are still possible withoutdeparting from the essence of the invention. The scope of the inventionis limited by the accompanying claims.

1. Rooftop canvas comprising: a twill texture layer including aplurality of flat warp strips extending in a longitudinal direction anda plurality of flat weft strips extending in a lateral directionperpendicular to the longitudinal direction, with an imaginary linepassing through an intersection of one of the plurality of flat weftstrips and one of the plurality of flat warp strips and an intersectionof another of the plurality of flat weft strips adjacent to the one ofthe plurality of flat weft strips and another of the plurality of flatwarp strips adjacent to the one of plurality of flat warp strips beinginclined relative to the longitudinal direction and the lateraldirection; and a first covering layer, with the twill texture layersuperimposed on the first covering layer.
 2. The rooftop canvas asclaimed in claim 1, with each of the plurality of flat warp strips andthe plurality of flat weft strips including at least one corrugatedface, with the twill texture layer including at least one corrugatedsurface.
 3. The rooftop canvas as claimed in claim 1, furthercomprising: a second covering layer, with the first covering layersandwiched between the twill texture layer and the second coveringlayer.
 4. The rooftop canvas as claimed in claim 1, wherein each of theplurality of flat warp strips and the plurality of flat weft strips ismade of polyolefin.
 5. The rooftop canvas as claimed in claim 1, whereinthe first covering layer is made of polyolefin.
 6. The rooftop canvas asclaimed in claim 3, with the second covering layer is made of one of athermoplastic elastomer, a polyolefin elastomer, or a polyolefinplastomer, or a mixture of polypropylene and at least one of athermoplastic elastomer, a polyolefin elastomer, and a polyolefinplastomer.
 7. The rooftop canvas as claimed in claim 4, wherein thepolyolefin is polypropylene.
 8. The rooftop canvas as claimed in claim5, wherein the polyolefin is polypropylene.